| 摘要 |
PROBLEM TO BE SOLVED: To provide a manufacturing method of a polyester by a continuous process where a glycol formed in the manufacturing process of the polyester is recycled. SOLUTION: In the continuous manufacturing method of the polyester comprising subjecting a slurry of an aromatic dicarboxylic acid and the glycol to an esterification reaction in an esterification tank and polycondensing the thus-obtained polyester oligomer in a polycondensation reaction tank, the glycol distilled out from the polyester manufacturing process is fed to a distillation column installed in the manufacturing process to fractionally distill and remove a low-boiling fraction mainly composed of water while recycling the residue taken out from the bottom part of the distillation column as a recovered glycol, where the following requirements are simultaneously satisfied: (1) The water content in the recovered glycol is controlled within a specific range. (2) The temperature of the slurry is controlled within a specific range. (3) The carboxy terminal group concentration of the polyester oligomer at the outlet of the final esterification reaction tank is continuously detected on line and the esterification reaction and/or the polycondensation reaction are controlled based on the detected value. COPYRIGHT: (C)2007,JPO&INPIT
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